Unit EARTHQUAKE GEOLOGY AND SEISMIC RISK

Course
Geosciences for risk and environment management
Study-unit Code
A002126
Location
PERUGIA
Curriculum
Geologia applicata alla salvaguardia e alla pianificazione del territorio
Teacher
Francesco Mirabella
Teachers
  • Francesco Mirabella
Hours
  • 42 ore - Francesco Mirabella
CFU
6
Course Regulation
Coorte 2021
Offered
2022/23
Learning activities
Caratterizzante
Area
Discipline geologiche e paleontologiche
Academic discipline
GEO/03
Type of study-unit
Obbligatorio (Required)
Type of learning activities
Attività formativa monodisciplinare
Language of instruction
Italian
Contents
Review of Rock mechanics, fracturing and faulting, friction and pore pressure, rheology and seismogenic layer thickness;
-Review of earthquake seismology, seismic waves, magnitude, focal mechanisms;
-Tectonic geomorphology, fault scarps, river and marine terraces, tectonic-induced perturbation of the river network;
-seismic cycle, characteristic earthquake;
-paleoseismology, dating methods for the Quaternary; seismogenic structures;
-seismic hazard, risk, vulnerability, elements of microseismic zoning.
Reference texts
-Yeats R., Sieh K., Allen C. The Geology of earthquakes. Oxford University
Press. 1997
- Burbank D.W. and Anderson R.S. (2001): Tectonic Geomorphology. Blackwell Science, 274 pp.
- McCalpin J.P. (2009): Paleoseismology. Academic Press, 2nd edition, 613 pp.
- Schumm S.A., Dumont J.F. and Holbrook J.M. (2000): Active tectonics and alluvial rivers. Cambridge University Press, pp. 276.
Educational objectives
The objective of the course is to provide the students the bases to identify and characterize seismogenic sources through the integration of geological, geomorphological, geophysical and seismological data. The course will be also dedicated: i) to the integration of Quaternary geological data, tectonic geomorphology and structural geology to reconstruct the recentmost tectonic evolution of active fault systems; ii) to recognition and the analysis of geomorphological markers to estimate the deformation rates of tectonically active areas; to the planning of paleoseimological surveys to reconstruct the Holocene tectonic activity of active faults; iii) to the application of geochronological techniques to date recent faulting events; iv) to the application of the knowledge to reduce the seismic risk.
Prerequisites
A basic knowledge of structural geology, geomorphology, seismology, Quaternary geology.
Teaching methods
The course is held through classes, seminars, the reading and comprehension of scientific articles, field excursions.
Learning verification modality
Oral exam
Extended program
1. Definition of earthquake: Worldwide distribution of earthquakes, plate tectonics.
2. Mechanical conditions for the enucleation of an earthquake, stress and strain, Anderson theory, Coulomb criterium, Griffith criterium; frictional reactivation,role of pore fluid pressure on fracturing and faulting, rheological profiles, brittle-ductile transition, factors affecting the depth distribution of earthquakes;
3. Seismological faults: types of seismic waves, epicenter, hypocenter computation, focal mechanisms. Magnitude and seismic moment; distribution of earthquakes on the basis of kinematic and depth.
4. The seismic cycle, recurrence models, characteristic earthquake, Richter and MCS scale, historical earthquakes, comparison of active deformation data and state of stress and with geological structures.
5. Deformation rates in the far-field and in the near-field; methods of identification of deformation rates: GPS, geodetic leveling, DinSAR.
6) Geological faults, fault dimensions in relation with magnitude, fault growth and segmentation, effect of fault interaction on fault growth and maximum magnitude; examples of paleo-earthquakes registered in rocks.
7) Geological methods of investigation of active faults using the ratio between erosion/sedimentation and tectonics, quaternary geology, crosscutting relationships, landscape and hydrological response to active tectonics; paleoseismological investigation and high resolution geophysical data; relationships between fault dimension and expected magnitude; co-seismic effects due earthquakes; cumulated expression of earthquakes; comparison between paleo-strain derived from geological faults and focal mechanisms, exmaples from recent earthquakes.
8. Tectonic geomorphology; acquisition of high resolution digital topography; the use of tectonic geomoprphology to investigate mid-term deformation; marine and river terraces and markers, hypsometric curve, asymmetric factor, estimation of river incision with the stream power, mapping and dating of river terraces.
9. Reconstruction of fault geometry to hypocentral depth, projection of earthquakes on geological cross-sections.
10. Dating methods,14C, U/Th, OSL, cosmogenics, tephfrochronology, paleomagnetism, dendrochronology, etc.., application ranges.
11. Seismic risk, seismic hazard, seismotectonic sources, site effects; innovative methids of seismic hazard, individual seismic sources.
Elements of microseismic zoning, levels of study, definition of the homogeneous microzones in a seismic perspective, stable, potentially unstable and unstable areas.
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